It is known in the art that compressed air, which has several uses including in breathing air systems, food packaging, pharmaceutical labs and integrated circuit manufacturing, may be treated to remove contaminants and water vapor. Compressed Breathing Air (CBA) may be produced by a breathing air purification system (BAPS). A BAPS may be employed for two primary functions: (i) dehydration to remove excess moisture from untreated air and (ii) purification to remove solid particles, oil aerosols and hydrocarbon vapors from untreated air. The purification function of the BAPS may also be configured to convert carbon monoxide to carbon dioxide.
Portable and stationary BAPS may be used to supply purified CBA to masks, helmets and hoods. CBA systems may be used to provide breathing quality air to workers engaged in tasks like firefighting, sandblasting, spray painting, chemical spill clean-up, welding, grinding, pipe and tank cleaning and similar activities where repeat exposure to untreated air can pose a health threat. Federal regulations require that CBA be used in environments where untreated air may produce physical discomfort immediately, chronic poisoning after repeat exposure, or acute adverse physiological symptoms after prolonged exposure.
Conventional BAPS typically utilize desiccant or refrigerated dryer technology to dehydrate the compressed air. Both of these devices are not very portable and require electricity or complicated and expensive pneumatic controls to operate. It is desired to provide BAPS having enhanced portability and reduced manufacturing costs while eliminating the need for any external utility (other than compressed air) while removing water, liquid oils, liquid contaminants, oil vapor, carbon monoxide and detectable odors from compressed air.
Furthermore, some conventional BAPS, such as those utilizing desiccant dryers, require sweep (purge) air for efficient operation. If this sweep air is taken from a point in the system prior to purification of the air, the sweep air may contain deadly contaminants, such as carbon monoxide. The sweep air is then expelled from the system into the immediate environment, potentially contaminating the surroundings. It is desired to provide BAPS which produces Occupational Safety and Health Act (OSHA)-quality Grade D breathing air without contaminating the installed area or immediate environment of the system.